Rim or tire making weird sounds.?

I recently changed out an aluminum rim for a steel one on my right front tire. It's been sealed and the tire itself is not leaking or rubbing. But whenever I go over 40 mph, it starts to make an odd low humming sound. Like an airplane. And I can feel the vibrations from the driver side. Anyone know what could be causing it? And is it safe to be on the highway with my car?